Because of distinguished flexibility, substantial resistance against degradation in the environment during use, and distinguished resistant properties against heat and chemicals, normally, polyimide fluorocarbon resin laminated films are used in the form of insulation material of electric wires and a variety of motors. When being used, a polyimide fluorocarbon resin laminated film is formed into tape, the tape-form film is wound on copper wires via a taping machine, and then the film is thermally adhered with fluorocarbon resin via predetermined thermal treatment. In this case, since substantial tension is added to the tape-form film, unless the polyimide film is fully adhered to the fluorocarbon resin layer, the polyimide fluorocarbon resin laminated film incurs peeling to result in difficult processing work.
Because of this problem, whenever processing such a polyimide fluorocarbon resin laminated film, it has been demanded that fluorocarbon resin be solidly adhered to a polyimide film. In order to promote adhesion between a polyimide film and a fluorocarbon resin layer in the course of producing such a polyimide fluorocarbon resin laminated film, superficial reformation of the polyimide film and reformation of the fluorocarbon resin have thus been executed.
Recently, owing to outstanding dimensional stability, thermal resistant property, and mechanical characteristic, polyimide fluorocarbon resin laminated films have also been used to form a masking tape of a film capacitor in particular. Such a film capacitor comprises a base PET film on which a metallic layer pattern is formed. In the course of producing such a film capacitor, for example, a tape-form polyimide fluorocarbon resin laminated film is placed on a base PET film, and then, after executing a process for adhering vaporized aluminium, a variety of metals are laminated, and finally, the polyimide fluorocarbon resin laminated film is removed therefrom to eventually form a metallic layer pattern on the PET film.
Nevertheless, in the case of using such a polyimide fluorocarbon resin laminated film to form a masking tape of a film capacitor, even though adhesion between a polyimide film and fluorocarbon resin layer of polyimide fluorocarbon resin laminated film may have been improved, if fluorocarbon resinous layer were insufficiently adhered with aluminium in the course of adhering vaporized aluminium, metal portion adhered to the film could easily be peeled while removing polyimide fluorocarbon resin laminated film in the following process to result in the generation of dust as another problem.